Retractable landing gear for aircraft



Aug. 31, 1948. E. E. WALLACE RETRACTABLE LANDING GEAR FOR.AIRCRAFT 8 Sheets-Sheet 1 Filed April 14, 1945 Aug. 31; 1948. E. E. WALLACE 2,443,064

RETRACTABLE LANDING GEAR FORAIRCRAFT Filed April 14, 1945 8 Sheets-Sheet 3 INV ENT OR.

Aug. 31, 1948. E. E. WALLACE 2,443,064 I RETRACTABLE LANDING GEAR FOR AIRCRAFT Y Filed April 14 i943 a Sheets-Sheet 4 Aug. 31, 1948.

E. E, WALLACE RETRACTABLE LANDING GEAR FOR AIRCRAFT 8 Sheets-Sheet 5 Filed April 14, 1945 FIG Hb Aug. 31, 1948. E. E. WALLACE 2,448,064

RETRACTABLE LANDING GEAR FOR AIRCRAFT I Filed April 14, 1945 s Sheets-Sheet a FIG 10 INVENTOR. 6W 621 Aug. 31, 1948. E. E. WALLACE RETRACTABLE LANDING GEAR FOR AIRCRAFT 8 Sheets-Sheet 7 Filed April 14, 1943 /I/I//////// I IN VENTOR.

Aug. 31, 1948.

Filed April 14, 1943 E. E. WALLACE RETRACTABLE LANDING GEAR FOR AIRCRAFT \llln 8 Sheets-Sheet 8 KB/ a Patented Aug. 31, 1948 RETRACTABLE LANDING GEARFOR AIRCRAFT Edward E. Wallace, Cleveland Heights, Ohio;

Daisy '1. Wallace, administratrix of said-Edward E. Wallace, deceased;-

Application April 14, 1943. Serial No. 482,991

18 Claims. 1

an improved airplane having landing gears and pairs of auxiliary devices retractibly mounted in thebody structure of. the airplane forward and rearward of its landing gears and arranged to 00 operate therewith under various operating conditionswhere land surfaces are flat or uneven.

Another object of the invention isto proivde an improved airplane having at one end thereof a retractible mechanism arranged to be operated into projected position, whereby the airplane may be shifted about its center of gravity or laterally to right or level it or position it for take-off dependent on the condition or unevenness of the terrain.

Another object of. the invention is to provide an improved airplane having at the rear. end thereof .a retractible mechanism arranged. to be operated intoprojected position for engagement withthe surface to support the rear end of the airplane while at rest or preparatory for maneuvering or take-off thereof.

Another object of the invention is to provide an improved airplane having at one end thereof a pair of relatively movable devices each arranged to be projected varying distances to compensate for uneven surface conditions to suppOrt the airplane in stabilized position.

Another object of the invention is to provide an improved airplane having at one end thereof combined shockabsorbing and leveling devices.

A further, object of the invention i to provide an improved airplane having a landing gear and retractible mechanisms at its opposite ends arranged. to be projected into engagement with the ground, whereby either end may be elevate-d and/ or righted to move the plane into a stabilized position or position it for a take-01f, dependent upon various conditions of the ground where a landing has taken place.

A'further object of the invention is to provide an improved airplane having at one end thereof a retractible mechanism adapted to co-operate with the landing gear to facilitate landing on 2 uneven surfaces and operable to elevate the plane after landing into stabilized position and/or to facilitate take-off.

A still further object of'the invention is to provide an improved airplane having a landing gear and retractible shock absorbers adjacent one end of the fuselage arranged to co-operate with the landing gear in making landings.

Afurther object of the invention is to provide an improved tire for those parts of an airplane which are or may be used in making landings and take-offs or for maneuvering operations.

A further object of the invention is to provide an improved airplane having at one end a wheel mounted supporting member which may be rotated prior to or after making a landing. to position the wheel for steering on different radii determined by the speed of the airplane.

A further object of .the invention i to provide an improved airplane having at one end of its fuselage a steerable wheel and power means for steering theiwheel, whereby the airplane may be s'teered'independently of the speed thereof or. speed of its propeller.

Other objects of the invention will be apparent to those skilled in the art to which my invention relates from the following description taken in connection with the accompanying drawings, wherein Fig. 1 is 'a plan View of an airplane embodying my invention.

Fig. 1a is a fragmentary section on the line la -laof Fig. 2, enlarged.

Figs. 1 1c and 1d are diagrammatic views.

Fig. 2 is a front elevation of the airplane when at rest on the ground or landing urface; the front retractible mechanism being in normal position within the hull.

Fig. 3: is a View similar to Fig. 2, but showing the airplane in'flight, its landing gears and retractible mechanisms being in retracted position.

Fig. 4 'isa side elevation of the airplane in flight.

Fig. 5 is a side elevation, showing the airplane at rest with the front and rear retrac-tible mech anisms projected into engagement with the ground and supporting the airplane in leveled position-and against movement due to external forces;

'Fig. dis. a side elevation showing the airplane in landing-position or in position for maneuvering on the ground or for taking off.

Fig. '7 is a side elevation showing the position of-the forward retractible mechanism when makinga landing under certain abnormal conditions.

Fig. 8 is a section on the line 88 of Fig. 4, looking towards .the right.

Fig. 8a is a fragmentary plan view on the line 8a-8a of Fig. 8.

Fig. 8b is a section on the line Bb-Sb of Fig. 8a.

Figs. 8c and 8d are fragmentary bottom plan views on the lines 8c--3c and. 8d8d, respectively, of Fig. 8, the cover in the former view being broken away.

Fig. 9 is a section on the line 88 of Fig. 4, looking toward the left, parts being in sections; the retractible devices being in one projected position.

Fig. 9a is a diagrammatic view of the pumps and motors therefor for one of the retractible mechanisms, generator and storage batteries for supplying current to the motors, engine for driving the generator and the sets of switches for the circuits for the motors for both mechanisms.

Fig. 9b is a fragmentary elevation showing one of the fluid pumps and the motor for driving it.

Fig. 10 is a fragmentary elevation of parts shown in Fig. 9, the wheel carrying members being shown in position to permit steering of the airplane in maneuvering on the ground,

Fig. 10a is a fragmentary elevation showing one of the wheel carrying members extended and rotated for steering or maneuvering operations.

Fig. 11 is a View substantially similar to Fig. 9, but showing the retractible devices in different projected positions.

Fig. 11a is a fragmentary view, partly in section, related to Fig. 11 to show the outermost position of one of the re-tractible devices.

Figs. 11b, 110, 11d are sections on the lines lib-l lb, lo, and l|dl Id, respectively, of Fig. 11.

Fig. lle is a section on the line l|eHe of Fig. 11, the parts being enlarged.

Fig. 111 is a fragmentary side view of parts shown in Fig. 11c, partly in section.

Fig. 119 is a section on .the line [lg-Hg of Fig. 11).

Fig. 11h is a view on the line llh-I Ih of Fig. 11e.

Fig. 12 is a fragmentary view showing the valve in normal or closed position.

Fig. 12a and Fig. 12b are views similar to Fig. 12, but showing the valve in its operated positions, respectively.

Fig. 13 is a fragmentary section of parts shown in Figs. 4, 5, 6, 7, 8, 9, 10, 11, 11b and 12, enlarged.

Fig. 14 is a view of the parts shown in Fig. 13, but in the position they occupy when a landing is taking place.

Fig. 14 is a fragment section of parts shown in Figs. 13 and 14, enlarged.

Figs. 15, 16 and 1'7 are sections on the lines I -I5, iii-16 and I'l-l'l, respectively, of Fig. 14.

In the drawings, i indicates as an entirety an airplane comprising a fuselage 2, wing structures 3 at opposite sides of the fuselage, ailerons 4, flaps 4', a rudder 6, elevators I, landing gears 8 and propellers 9 driven by one or more suitable motors (not shown). In the illustrated type of airplane, each wing structure consists of a wing 3a. and a sponson 3b, the latter being constructed .to house the adjacent landing gear 8 (see Figs. 1, 3 and 4) whereby landings on and take-offs from water may take place. In the form of airplane disclosed, it is designed to have a gross weight of 400,000 pounds. The airfoil span is approximately 260 feet, the overall length approximately 185 feet and a height (when the landing gears are in operating position-see Figs. 2 and 5) approximately 45 feet; accordingly, this size of airplane makes it necessary to provide it with more than one engine, for which reason I have shown mounted on each airfoil 3a two propellers 9, which may be drivingly connected to one engine or each propeller driven by one or more engines; the engine or engines also being suitably mounted in the adjacent airfoil 3a or adjacent thereto.

It will be understood that the airplane may be of any desired size and that the number of engines required will depend upon the size of the plane and other factors.

The parts above referred to, may be of any desired shape and form of construction and the engines and propellers may be variously mounted, as they form no par-t of the present invention. As will be apparent, (a) the engines, (b) controls for and connections to the elevators 7, rudder 6, ailerons 4 and the engines, (0) flying instruments, such as gages and the like and (d) fuel and oil tanks for the engine, and electrical and other equipment, utilized for propelling the airplane are not shown as these parts, accessories and equipment may be of any well known construction and form no part of the present invention.

The herein disclosed construction of the landing gears, their operating mechanisms and housing thereof form the subject-matter of my co-pending application Serial No. 431,102, filed February 16, 1942 now U. S. Patent 2,415,615 of February 11, 1947.

As shown in Figs. 2 and 3, the lower portion of the fuselage is constructed to provide a hull ID the bottom wall of which preferably consists of inclined portions l0 extending from the lateral sides or chines of the hull l0 downwardly and inwardly to the keel forming a V-shaped bottom.

However, in showing herein a sesque amphibian type of plane, it is to be understood that the invention may be applied to and incorporated in other types of airplane, whether the landing gears are fixedly related to the fuselage thereof or retractible into an inoperative position. Accordingly, the use of the term hull is merely for descriptive purposes and not intended to be limiting.

Each sponson 3b is fixedly related to the hull l0 and is (a) provided interiorly with a comparte ment or chamber opening downwardly, but closed by doors 3c, 3d, 3e, to house the adjacent landing gear 8 (see dotted lines in Fig. 1), when landing on and taking off from water and when the plane is in flight as set forth in my aforesaid application and (b) suitably reinforced and braced interiorly in any desired manner. The reinforcing and bracing structure for each sponson forms no part of the present invention.

ll indicates as an entirety a retractile mechanism mounted in the hull forward of the landing gears 8, preferably adjacent the front end of the hull and Ha indicates as an entirety a retractile mechanism mounted in the hull rearward of the landing gears 8, preferably adjacent the rear or tail end of the hull. Each mechanism ll, Ila, may consist of a single retractile member operated in the manner later set forth, the member for one mechanism being mounted forward of the landing gears and the member for the other mechanism being mounted rearward thereof. When each mechanism is of this form of construction, the member is mounted in line with the longitudinal axis of the hull. By prefsame eat n mechanism 11, Net, consists of two members indicated as an entirety at I2, I2a, respectively, operable together or separately by fiuidsupplied under pressure, from a position the hull H] outwardly to predetermined positions, whereby either or both mechanisms or one or more members thereof may cooperate with the landing gears under different conditions. g

Each= of the members I2, I2a, is provided with shook-absorbing means, indicated as an entirety at I3 and is provided at its outer or ground engaging end with a wheel l4, comprising hub or rim arid a tire, which may be of any desired form of construction, but for purposes of illustration the; wheel I4 (more particularly the tire thereof) embodies certain improvements, set forth in my co perrding application filed May '7, 1943, Ser. No. 485,979, for which reason no claim thereto is made herein. This application has now matured into U. s. Patent 2,365,944) of August 29, 1944'.

Also, as later set forth, each member I2, I2a, is rotatable to position the axis of the wheel I4 at varying angular relations to the longitudinal axis or the hull Ill, whereby the wheel may be positioned to permit steering or maneuvering of the airplane on the land or other surface. As will be later set forth, elements of each member I2, 1 2a, are movable outwardl relative to the hull IG, toward the ground and upon engagement therewith, if the application of the power means iscontinued, the relative movement will, in a paradoxical sense, be reversed, that is, that element which engages the ground will be arrested with respect thereto and the hull It) will move upwardly relative to the ground, thereby moving the adjacent end of the hull I upwardy to the desired position. On the other hand, reverse movement of these elements will permit the hull Hi to gravitate downwardly, unless such movement is prevented by the landing gears and/or other of the retractibl'e members.

It will also be noted that the members I2, IZa, of each mechanism II, I Ia, are arranged sideby-side and preferably so mounted that the movabl'e'elements of the members move on axes which convergeupwardly and intersect the central longitudinal axis of the airplane (preferably that axis which cuts the center of gravity of the airplane) for obvious reasons in making a landing or leveling the airplane at any time to prevent lateral thrusts or tipping movement thereof when these members engage the land or other surface.

the arrangement herein disclosed, the ground engaging element of each member I2, l 2 'a' is' movable outwardly a total distance of approximately 25 feet, but each member is so constructed that by control of the power means therefor the ground engaging element may be moved outwardly (a) approximately 5 feet to one predetermined position (which position may be termed its landing position) or a lesser distance, (1))- approximately 12 feet farther to a second predetermined position (which position may be termed its first levelin position) or a lesser distance and (0) approximately 8 feet farther to a third predetermined position (which may be termedits second leveling, tilting or extreme outermost position) or a lesser distance. Accordingly, when a landing is to be made the members I2, IZa, are projected to the first predetermined position (Fig. 7), whereby they may act as shock absorbers. After the landing is made, one orm'o're members may be operated to move the hull I0 into another position; For example (:1)

6 if the airplane in landing come to rest in the position shown in Fig. '7, the members I2, I2a', of the mechanism II may be projected a greater distance outwardly, as shown in dotted lines in Figs. 5 and 6, the effect of which is to rockthe' hull-shift its center of gravityto the position shown in Fig. 6; (b) if the airplane is to be leveled, both members of both mechanisms II; IIa, may be operated to the positions shown in Fig. 5; (c) if the airplane is at rest in the position shown in Fig. 6 and a strong wind is blowing from the right, as viewed in Fig. 6, the members of the rear mechanism may be projected outwardly a greater distance, as shown in dotted lines in Fig. '7, the effect of which is to rock the hull to the position shown in full lines in Fig. '7 so that the wind in acting on the wings will create a down-force on the airplane, and (d) where the terrain below the hull I0 is uneven, the members I2, I'2a, of one or both mechanisms may be projected different distances (see (Fig. 11), to level the airplane as shown in Fig. 5.

As will be observed in Fig. 6, the members of the rear mechanism Ila whenmoved or projected to their first predetermined position serve asskids in making a take-off or in maneuvering the airplane into loading, unloading and takeoff positions. By projecting all of the members into engagement with the ground (see Fig. 5)-, the airplane may be supported in any desired position, that is, horizontally or otherwise. When the airplane is in flight, the members of both mechanisms may be retracted within the hull II) to eliminate drag. By control of the power means for each member, the ground en-' gaging element thereof may be moved inwardly toward its retracted position or to any desired projected position.

As each member I2, IZa, is similar in construction, only one is referred to, but the same reference characters are used to identify like parts in all views and in describing one member reference is made to other members for a complete understanding of the construction.

Each member I2, I200, consists of a plurality of hollow, concentrically related, elements, relatively movable endwise and suitably keyed together (as later set forth) for rotative movement as a unit, to change the position of the wheel I4 as already set forth. As later set forth, the elements are constructed so that one element serves as a piston and the adjacent element serves as a cylinder, whereby by means of a fluid supplied under pressure and/or a fluid under static or negative pressure, due to the control of the power means, which comprise, suitable pumps (later referred to), relative endwi'se movement of the elements may be effected to'move one or more of the elements outwardly predetermined distances (Figs. 9, 11 and l l-a) as already set forth and move all of the movable elements inwardly to any desired position or into their retracted or normal position (see Fig.

I 6 indicates the outer element rotatably mountedin the hull If its upper end being provided with an annular end wall Ifia to form a stop for the adjacent intermediate element H, which is provided at its upper end with an external annular shoulder Ila slidably fitting the inner wall'of the element I8. At its lower end, the element I6 is provided with an internal annular shoulder I6b slidably fitting the outer Wall of the element IT and forming a stop for the shoulder Ha to limit the outward movement of the element H. The sheulder rm serves as a piston when fluid under pressure is supplied to the space betweenthe elements I I5, II, whereby the latter element is moved inwardly into engagement with the wall I6a. The element It is formed with an opening I60 adjacent to the stop I6b. The opening I60 is connected to a supply and discharge pipe IBm which is connected to a suitable pump 23 (later referred to) that portion of the pipe I61: connected to the opening I60 is flexible to compensate for the rotative movement of the element IS. The space between the elements I6 and I1 is maintained filled with fluid, under static pressure, as shown at a, to lock the element I'I against movement, until the pump connected to the pipe Ifix is set in operation to relieve or set up a negative pressure by withdrawing the fluid from this space. As shown, the upper end portion of the outer element I6 rotatably fits a split bearing Ific', the inner member of which is supported by a gusset I60". The lower end of the element It is provided with an external flange Hid which rotatably engages a bushing I6 suitably fixed to the adjacent chine I and surrounding an opening Illb through which the movable elements project. A cap I6", which is provided internally with screw threads and threaded on the bushing l6, engages the flange I6d of the element I6 to hold it in engagement with the bushing I6. The opening IUb is provided with a hinged closure I00, its hinge devices being acted upon by a suitable spring (not shown) which normally tends to swing the closure into closed position (Fig. 8). By removing the cap l6 and outer member of the split bearing IBc, the member I2 may be bodily removed from the hull II). To permit of the removal of either or both members I2, I2a, the adjacent top wall of the hull Ill is formed with an opening Illa which is closed and suitably sealed by a cover Ilib by means of screws I00.

The means for rotating the element I6 and through it the other elements of the member I2, are referred to later. The element I1 is provided with a stepped portion H1) at its lower end to form a shoulder I'Ib remote therefrom. I8 indicates that element which in efiect constitutes the ground engaging device of the retractible member. The element I8 slidably fits the inner Wall of the stepped portion I'Ib of the element I! and is provided at its upper end with a collar I8a (preferably formed integrally with the walls of the element) which slidably fits the inner wall of the element I'I. Remote from its outer end, the element is is provided with an annular rib I 8b (preferably formed integrally therewith) arranged to engage the shoulder IIb, so that when the element I8 is moved to the first and second leveling positions, the element I! will be moved like distances to form a support for the element I8 between it and the element IS. The rib I 8b is preferably positioned on the element I8 so that when the elements are in normal position, it is spaced approximately five feet from the shoulder I'Ib'. In this arrangement, when the element I8 is moved to its landing position, as shown at the left side .of Fig, 11, the rib I8b will be in position to engage the shoulder Nb and move the element I'I outwardly therewith. 18a: indicates a transverse wall within the element I8 remote from its outer end to form a chamber I830 within which the shock absorbing means I3 are mounted and to provide a piston against which the fluid under pressure is applied to move the element I8 outwardly, as later set forth. I9 indicates a head fixed to or formed integrally with the lower end of a tubular element I9a, the upper end of which is soldered or welded to the inner wall of the stop [6a. 20 indicates an element slidably fitting the inner wall of the element I8. At its lower or inner end the element 20 is provided with an end wall 20a which forms a head for the piston I82: of the element I8 and a piston for the element 20 when the fluid under pressure is supplied to move the element 20 outwardly. The inner wall of the element 20 slidably fits the head I9. The upper end of the element 20 is provided on its inner -wall with a collar 201) which slidably fits the outer wall of the tubular member I9a. As shown, the diameter of the tubular member I9a is smallor than that of the element 20 to form between the head I9 and the collar 2% an annular chamber 200 which is filled with fluid under static pressure as shown at b, to lock the element 20 against movement when fluid pressure is applied to the piston l8a: to move the the element I8 to its landing position. The lower end of the chamber 2110 is suitably connected to the inner end of a supply and discharge pipe 2| for the fluid, which pipe extends through the tubular member I9a, being connected at its outer end to a flexible pipe 2 Ia, which in turn is connected to a suitable pump, as later set forth. The pipe 2| is smaller in diameter than the tubular member I9a, so that the latter may serve as a conduit for fluid under pressure for the pistons I81: and 20a. As shown, the head I9 is formed with a through opening I92) and the piston 20a is formed with a through opening 20a in registry therewith, to permit the application of fluid pressure against the piston I81: to move the element I8 to its landing position (Figs. 9 and 10). The upper end of the tubular member Illa is connected to a nipple 22 which in turn is connected to a pipe 22a leading to a suitable pump (later referred to) that portion of the pipe 22a connected to the nipple 22 being flexible to compensate for the rotative movement of the tubular member I9a with the elements I6, I! and I8. As the tubular member is connected through the nipple 22 and pipe 22a with a pump, it is at all times maintained filled With the fluid. As shown in Figs. 8, 9, and 11, the outer face of the Wall 20a is relieved to form a space for the fluid, whereby initial pressure may be applied to the wall I83: and the outer face of the head I9 is relieved to form a space for the fluid, whereby initial pressure may be applied to the wall 20a.

The power means for each member I2, I2a, consists of three pumps 23, 24, 25 (see Fig. 9), each driven by a motor 26 (see Fig. 9b). The pumps are preferably of the rotary type and of any standard or preferred construction. One side of each pump is connected by a pipe or conduit 21 to a sump or reservoir 27a for the fluid, such as oil. The opposite side of pump 23 is connected to the pipe Him for the adjacent retractible member; the opposite side of pump 24 is connected to the pipe 22a for the adjacent nipple 22; and the opposite side of pump 25 is connected to the pipe 2 Ia for the adjacent discharge pipe 2|. The pumps are operable in opposite directions and separately controlled to effect relative movements of the elements forming the adjacent retractible member in the manner lat r set forth. Accordingly, each pipe connected to each pump forms both a liquid supply and discharge dependent upon the direction of rotation of the-pump.

Operation: assuming that the elements of the member IZa of the mechanism are in normal position (Fig. 8) and it is desired to move them to the landing position (Fig. 9), the pump, 24 is op- .9 erated to draw fluid from the sump 21a to efiect flow therefrom to and through pipe 22 to the tubular member I9a and openings I9b, 20a, the effect of which is to apply the pressure to the pieton 18:1! and move the element I8 outwardly to ings 2011, I91), and discharge the fluid into thev sump 21a.

This negative pressure will be effective to draw the piston I80: inwardly and thereby retract the wheel I4 into normal position (Fig. 8)

If it is desired to project the element l8 from the landing position (Fig. 9) to the first leveling position (as shown at the right side of Fig. 11), (a) pump 24 is operated to effect flow of the fluid under positive pressure through the tubular member I9a and openings I91), 2011', into the element I8, the eiTect of -which is to apply pressure to the piston I81); and. (1)) pumps 23 and 24 are operated simultaneously to set up a negative pressure in the pipes I53: and 22 to withdraw the fluid from the spaces between the elements I5 and I! and between the tubular member I90! and element 20, such withdrawal of the fluid serving to permit the elements I1 and to move outwardly with the element I8. In carrying out this operation, it will be observed that through the engagement of the rib I8b with the shoulder IIb', the element U will be moved outwardly with the element I8, and the pressure of the fluid supplied by the pump 24 will move the element 2!] outwardly with the element I8. By reversing the pumps 23, 24 and 25, the elements I1, 20 and I8 will be moved inwardly to any desired position.

If it is desired to project the element I8 from its first leveling position (right side of Fig. 11) to its second leveling, tilting or outermost position (Fig. 11a), (a) pump 24 is operated to effect flow of the fluid under positive pressure through the tubular member I9a and openings I9b, 20a,

to apply pressure to the piston I83: to move the element I 8 outwardly, (2)) pump 23 is operated to withdraw fluid from the space between the elements I8 and I! and (0) pump remains stationary.

In carrying out this leveling or tilting operation, it will be observed that through the engagement of the rib IBb with the shoulder III), the element I'I will move outwardly with the element I8 to form a support for the latter element between it and the element I6. If the pumps 23 and 24 are reversed, the fluid under positive pressure will be supplied through the pipe I 6.1; to

the space between the elements I6 and I1 and applied to the collar Ila to return element H to the leveling position as shown in Fig. 11 and the element I! in turn, due to the engagement of shoulder I'Ib with the rib I827, will move the element I8 to its first leveling position due to the withdrawal of the fluid therefrom. Of the reverse operation of the pumps 23 and 24 is continued and pump 25 is operated to supply fluid through the pipe 2I to the space between the member Ida and element 20, the element I8 will be returned to its landing position, as shown in Fig. 9 and if such reversed operation of pump 24 10 is further continued and operation of pumps 23 and 25 is stopped the element I8 will be returned to its normal position.

It will be observed that prior to the operation of moving either or both members I2, IZa, from the landing position to their leveling or tilting position, due to the diverging relation thereof, the element I6 and parts connected thereto must be rotated 90, so that one or both wheels I4 are disposed at right angles to the fuselage (see Figs. 10 and 10a). When the elements are returned to the landing position, the members may be rotated to return the wheels I4 to normal position.

Suitable relief valves 231: are provided in the connections between the pumps and the sump so that in the event the pumps continue running, danger of stalling the motors which drive the pumps, is avoided.

It will be observed that the fluid systems above described are of the closed type, so that operation of each pump in either direction effects outward flow of the fluid through one pipe connected to the pump and inward flow thereto from the other pipe connected to the pump; also, during operation of the elements, stoppage of the pumps then in operation will effect stoppage of the elements. Accordingly, the element I8 may be moved outwardly and inwardly varying distances.

Certain of the elements of each retractile member I2, I2a, are keyed together so that when the rotating means H (which are connected to the element I6) are operated in either direction the element I8, which through the shock absorbing means I3 supports the wheel I4, may position the latter in position for forward travel of the airplane or at an angle to facilitate steering or maneuvering thereof. As shown in Figs. 8, 9, l1 and ill), the outer wall of the element I! is formed with a longitudinally extending insert which is formed with a keyway 28 and the inner :wall of the element 1,6 is provided with a spline 29 secured in position by countersunk screws (see Figs. 11 and 11b) and slidably fitting said keyway. As shown in Fig. lie, the inner Wall of the element I! is provided with a longitudinally extending insert which is formed with a keyway 3|] and the outer wall of the element I8 is provided with a key 3| secured in position by countersunk screws, and slidably fitting saidkeyway. As shown in Figure 1101, the inner wall of the element I8 is formed with a longitudinally extending insert which is formed with a keyway 32 and the outer wall of a member I3a, which forms part of the shock absorbing means I3 and carries the wheel I4, is provided with a key 33 secured in position by countersunk screws.

33a: indicates as an entirety mechanism for simultaneously rotating the members I2, I2a., of each retractile mechanism II, Ila, whereby the adjacent wheels I4 may be moved to various angular positions (preferably through an arc of degrees) for steerin the airplane when completing a landing or in moving the plane from time to time. These mechanisms are similar in construction so that onl one is illustrated and needs to be described. 34 indicates as an entirety means for rotating each member I2, IZa, of each mechanism II, No, whereby (a) each member may be rotated approximately degrees (see. Fig. 1.00.) when it and/or the member adjacent thereto or both of said members are to be adjusted outwardly or inwardly, so that one wheel I4 may have rolling contact with the ground or (12) both wheels I4 may be set in various angular positions (for example, at right angles to the longitudinal axis of the planesee Fig. for maneuvering the plane on the ground from time to time. The mechanisms 34 for operating the members 52, I211, are similar in construction, so that Only one thereof will be hereinafter described. The mechanisms 3300 and 34 operate independently of each other and also independently of the hydraulic means for moving the elements of each member l2, lZa, outwardly or inwardly, so that the rotation of the members may be efiected when in their retracted position or in any projected position thereof. Each mechanism 33a: is arranged to simultaneously rotate the adjacent members l2, l2a, from neutral position through an arc of 45 degrees in either direction, the wheels l4 being in neutral position when their axes are at right angles to the longitudinal axis of the airplane, whereas each mechanism 34 is arranged to-rotate the adjacent member from neutral position through an arc of 90 degrees in either direction. Of the rotatable means 33x, indicates a collar rotatably fitting the wall of the element It, a, portion of the outer wall of the collar 35 being provided with gear teeth 36, in mesh with a gear 31 fixed to a shaft which is provided with a second gear 38. The gear 38 is in mesh with a pinion 39 fixed to the shaft of a motor 30, which is suitably supported on the side wall of the element Hi, this gearing forming a lock between the collar 35 and the element l6, so that when the power is applied to the collar 35, the element It and parts connected thereto will be rotated, but by holding the collar stationary and operating the motor 40, the element It and parts connected thereto will be rotated relative to the collar. At one side, the collar 35 is provided with an arm ll (see Fig. lle) to which the outer end of a piston rod 42 is pivotally connected, the inner end of the piston rod 42 being provided with a piston 42a, which is reciprocatably mounted in a cylinder 43, so that by application of pressure to either side of the piston, the latter is operated to rotate theelement It. It will be noted that parts similar to those just described are provided for rotating the other element N5 of the adjacent retractible mechanism, so that both may be operated simultaneously, but by pref erence I provide operating connections, indicated as an entirety at M (later referred to) between the collars for the elements iii of the adjacent mechanisms to insure that these elements will be moved equal distances. The inner end wall of cylinder 43 is pivotally mounted on the keel of the hull I!) to permit it to bodily swing during rotative movement of the collar 35. When the element i6 is in normal position the piston 42a is disposed midway the opposite ends of the cylinder 43, so that pressure applied to either side of the piston will move it toward the remote end of the cylinder.

In the preferred form of construction I provide (a) fluid connections 45, to the opposite ends of the cylinder 43 for fluid under high pressure (approximately 100 pounds) supplied by a pipe 45a leading from a source of supply 45a, (b) fluid connections 45, 46, to the opposite ends of the cylinder 43 for fluid under low pressure (approximately 10 pounds) supplied by a, pipe 46a leading from a source of supply 46a and (c) a valve ll, which is normally closed (see Figure 12), for controlling the fluid supply to and discharge from the cylinder. The fluid employed consists of oil the quality of which depends upon climatic conditions under which the airplane is used. The valve element of valve 41 is provided with ducts 47a, 47b and 41b, so that in one position (Figure 12a) fluid under high pressure from the pipe 45a is supplied through the duct 41a to the connection 45 and cut off through the connection 35 and fluid under low pressure is cut oil through the connection 45 and completed through the connection 46 and duct 41?) to the pipes 46a, whereas in the other position of the valve (Figure 1212) fluid under high pressure from the pipe 65a is supplied through the duct lla to the connection 45' and cut off through the connection 45 and fluid under low pressure is cut off through the connection 46 and completed through the connection 46 and duct 41b to the pipe 46a, so that the piston 42a may be moved in either direction from neutral or any previously operative position.

As shown in Figure 11), the cylinder 43 at opposite sides of the piston 42a is always filled with fluid, so that when the valve i1 is closed, the piston (and all parts connected thereto) is locked against movement, but as set forth above where the valve connects the high pressure fluid supply to one end of the cylinder it connects the low pressure supply with the opposite end thereof. Accordingly, upon supply of the fluid under high pressure to one end of the cylinder the piston is moved toward the opposite end thereof, the fluid in the cylinder on the remote side of the piston being forced through the low fluid pressure connections to the pipe Mia and'through the latter to the low pressure supply 46a.

The shank of the valve element is provided with an arm 48 to which one end of a spring 49 is connected, its opposite end being suitably anehored to a bracket 49a which may be supported on the wall of the cylinder 43. The spring 49 is put under tension when the valve element is operated from neutral position in either direction, so that when the valve element is released, the spring 49 serves to return the valve to normal position, thereby closing the valve and cutting off the fluid connections with the pipes 45a, 45a, but as the cylinder 43 at opposite sides of the piston 42a is filled with fluid, the piston will he held against movement, so long as the valve 4? remains closed. The shank of the valve element is connected through a link to one end of a rod 50, which extends through a hollow support 5! and is provided with a core for a pair of coils also spacedly mounted in the hollow support 5i, The coils, the circuits for which are later referred to, and the core constitute a double acting solenoid 5!, so that by energizing one of the coils, the valve element of the valve 41 may be operatedin either direction. But upon opening of the circuit for the energized coil, the core is released and the spring 19 operates to move the valve element of valve A? to closed position and the core to neutral position ready to be acted upon by either coil of the solenoid. The hollow support 5! for the coils of the solenoid is preferably supported by brackets suitably secured to the walls of the adjacent cylinder 43. The construction of the double-acting solenoid and parts above described are more clearly shown in my co-pending application, Serial No. 455,894, filed August 24, 1942, and form the subjectmatter thereof, for which reason no claim is made to these parts, in themselves, herein.

The inner ends of the rods 58 for the solenoid cores preferably have sliding support in tubes 50a fixed at their inner ends to the opposite sides of the keel in relation to an opening therein.

The adjacent ends of the tubes 5pc are in registry so that a chain may be slidably mount ed in the tubes 59a, the ends of the chai ns being connected to the rods 50 to insure movement thereof equal distances when correspond-- ingly electrically related coils of the double acting solenoid are energized. In view of this connection between the rods 50, it will .be noted that the inner coil of each solenoid and outer coil of the other solenoid are connected in the same circuit and that the rods are so connected to the valve elements or the ducts therein are so arranged that the pistons 42a when operated will move in the same direction (leit or right Fig. lle), whereby the adjacent elements It will move simultaneously counter-clockwise or clockwise.

It will be observed .(a that by energizing one of the solenoid coils, the piston 42a may be moved from neutral position in either direction any desired distance within the range of movement thereof, and the valve closed by deenergiz ing the coil to lock the piston in operative position against movement and (b) that since the valve is closed at the end of each operation and the solenoid core is moved to its neutral position, the valve element may be operated to move the piston in the same direction or in the opposite direction dependent upon which solenoid coil is energized. By preference I provide a signal system whereby the neutral or operated positions of the pistons 42a, and hence the position of the adjacent wheels l4, may be indicated to the pilot.

As the collars 35 adjacent to and forming parts of each mechanism ll, Ha, are connected together by the connections 44 (later referred to), this signal system is related to only one cylinder and the adjacent collar. This system includes a panel 52 suitably supported in the cock-pit (Figs. 1a and 1b) and mounting the signal devices 52a (preferably consisting of lamps) designated (zeroposition) and 9, 18, 27, 36 and 45", respectively, at either side of 0, connected in a circuit 53 (Fig. 1c). The circuit 53 consists of a lead 5t connecting one side of the battery 53a to a movable contact 55 and a lead 58 connected to the opposite side of the battery and having branch leads 56a connected to a series of contacts 51, respectively, which are arranged to be engaged by the contacts 55, during movement of the latter. As a lamp 52a is connected in each branch lead 55a, the engagement of the contact 55 with the contacts 51 will light the lamps corresponding thereto respectively. As shown in Fig. lie, the contact 55 is engaged with contact 57 for that lamp 5 2a which indicates zero position, that is, the mid position of the pistons 42a, and normal position of the wheels I4.

If the rota means 33m is operated to rotate the collar 35 and element I6 to a predetermined position, the contact 55 will successively en age the contacts 5.! until that contact corresponding to the selected positionds reached, such movement of the contact 55 serving to momentarily successively light the lamps related to the engaged contacts 5? except the last engaged contact; the lamp 52a for the latter contact remaining lighted and indicating the operated position of the piston 42a and angular position of the wheels [-4. The contacts 51 are mounted in a U- nember 58, the sides of which are preferably supported on the walls of the adjacent cylinder 43, each contact 51 being slidably mounted in an opening formed in the U- member 58 and normally held in position for engagement by the movable contact 55 by a spring. The movable contact 55 is connected to the inner end of a tube 59, which is slidably mounted in the inner side of the U-member 58 and telescopes over a rod 60 supported at its outer end in the outer side of the U-member The outer end of the tube 59 is pivotally connected to the arm 4|, whereby the contact 55 moves with the adjacent piston 42a. The lead 54 is connected to one end of the rod 60, which forms the electrical connection for the circuit 53 from the lead 54 to the contact 55. This electrical connection as well as the mounting of the rod 60 and tube 59 and construction of the contact are preferably similar to like parts more fully shown in my aforesaid co-pending application to which reference may be made.

' The connections 44 comprise the following: 6] indicates rods each connected at its outer end by a suitableuniversal point to an arm 4 la: provided on the adjacent collar 35 in diametrical relation to the arm 4| thereon. The inner end of each rod Si is connected by a universal joint to the outer end of a link .62 the inner end of which is hingedly connected to a bracket fixed to the keel of the hull Ill (see Figs. 11c and 11f.)

The rotatable means 34 comprise the motor 40 and gears 39, 38, 31" and teeth 36 on the collar 35. As the adjacent collar 35 may be held stationary by the adjacent piston 42a, operation of the motor 45 will serve to rotate the adjacent element I6 relative to the collar and thus provide for movement of the adjacent wheel, whereby the wheel may be turned to an angle of By preference, I provide a signal system for each retractible member l2, lZa, whereby the neutral or angular position of each element. 16 and wheel I4 adjacent thereto when operated by the rotating means 34 may be indicated to the pilot. These signal means and the signal means above described are provided so that the pilot when in the cock-pit may determine the position of the wheels at any and all times, more particularly prior to a take-off or maneuvering of the airplane on the ground to avoid accidents, whereby the necessity for the pilot or other opera-v tive to inspect each wheel l4, preparatory to operation of the airplane, is eliminated.

The signal means for each rotating means 34 includes a panel 52' suitably supported in the cock-pit (Figs. la, 1?) and 1d) and mounting the signal devices 52a (preferably consisting of lamps) designated 0 (zero position) and 18, 36, 54, 72, and 99, respectively, at either side of 0, connected in a circuit 53. The circuit consists of a lead 54' connecting one side of a battery 53a to a contact, 55' mounted on the collar 35 and a lead 55' connected to the opposite side of the battery and having branch leads 5511. connected to a series of contacts 51, respectively, which, being mounted in an arcuate support 51a: mounted on the adjacent element 15, are arranged to successively engage the contact 55 as the element it rotates, each lamp 52a being connected in series in one of the branch leads.

Bea/ so that during rotation of the element IS the contacts 5] will successively engage the contact 55 to successively light the lamps 52a andwhen movement of the element l6 stops, the lamp remaining lighted will indicate the operated position of the element It and adjacent'wheel IA. The contacts 51' are preferably mounted in the support 51a: similarly to the contacts 51'. Lamps at 15 right of are preferably red; lamps at left of 0 are preferably green; to quickly indicate to pilot the direction of movement of the wheels.

As each member l2, [2a, of the mechanisms H, Ila, is operated independently, I provide (a) double acting switches 62, 62a, 62b, for closing the respective circuits to the motors 26 each of which may be driven in either direction for operating the pumps 23, 24, 25, for one retractible member of one mechanism and (1)) double acting switches 62, 62a, 62b, for closing the respective circuits to the motors 26, each of which may be driven in either direction, for operating the pumps 23, 24, 25, for the adjacent retractible 'member and (0) corresponding double acting switches (see diagrammatic Fig. 9a) for the circuits for motors 26 which operate the pumps for the retractible members l2, [2a, of the other mechanism; I also provide for one retractible mechanism a double acting switch 621: for closing the circuits to alternate coils of the solenoids 5| and double acting switches 629: for closing the circuits for operating each motor in either direction; corresponding switches for the circuits for the coils of the solenoids 5| and motors 40 for the other retractible mechanism being shown in Fig. 9a; the motors, pumps and other parts of the other mechanism being omitted from Fig. 9a to avoid duplication. The current for the circuits I for the motors 26 may be supplied by (a) a suitable battery 63, or (b) by opening a switch 63a and driving a generator 64 by a suitable motor 64a.

The supply of fluid under high pressure 450, consists of a tank (see Figure 9a) filled with fluid and air under pressure which acts to supply the fluid under high pressure through the valve 41 to the cylinders 43, as already set forth. The tank 65 below the fluid level therein is connected by a pipe 66 to the out-put side of a pump 6'! (which is driven by a motor 61), in the in-put side of which is connected by a pipe With the sump 21a, whereas the tank 65 above the fluid level is connected by a pipe 68 to one end of a The piston 10 is connected to one end of a rocker H, the opposite end thereof being engaged by an expansion spring 12, the rocker serving as one contact and arranged to engage a fixed contact 13, to close the circuit for the motor 67'. Accordingly, when the air pressure in the tank 65 is reduced below the predetermined pressure (100 pounds) due to the discharge of fluid therefrom to the cylinders 43, pressure on the piston 16 is relieved, whereby the spring 12 rocks the rocker 'H to close the circuit to the motor 61' which drives the adjacent pump 61 to draw fluid from the sump 21a and discharge it into the tank 65, the effect of which is to build up the pressure therein. The raising of the pressure in the tank 65 operates to move the piston Ill and through the rocker H to break the motor circuit.

The supply of fluid under low pressure consists of a tank 65a (see Fig. 9a) filled with fluid and air under a lower pressure as compared to the pressure in the tank 65. The tank 65a below the fluid level therein is connected by a pipe 66a to the out-put side of a pump 61a (which is driven by a motor 67a) the in-put side of which is connected by a pipe with the sump 21a, whereas the tank 65a above the fluid level is connected by a pipe 68a to one end of a cylinder 69a, in which is mounted a piston Illa. The piston 10a is connected to one end of a rocker Ha, the opposite end thereof being engaged by an expansion spring 12a, the rocker serving as one contact and arranged to engage a fixed contact 13a to close the circuit to the motor 61a. Accordingly, in the event air pressure in the tank 65a is reduced below the predetermined pressure (10 pounds), pressure on the piston 70a will be relieved, whereby the spring 12a will rock the rocker Ha and close the circuit for the motor 61a, which will drive the adjacent pump B'Ia to draw fluid from the sump 21a and discharge it into the tank 65a, the efiect of which will be to build up the pressure therein. The raising of the pressure in the tank 65a operates to move the piston 70a and through the rocker "Ha to break the motor circuit. Although provision is made for automatically maintaining a predetermined pressure in the tank 6511, it will be observed that in the operation of the valves 41 the supply of fluid under high pressure to each side of the pistons 42a in the cylinders 43, in each operation of the pistons, is effective to force the fluid in the cylinders on the remote side of the pistons through the low pressure fluid connections and pipes 46a to the tank 65a, so that under normal conditions the fluid in the tank 65a is not withdrawn therefrom; on the other hand due to the supply of the fluid to the tank 65a from the cylinders 43 I provide between it and the sump 21a a connection 74 having a relief valve therein, whereby excess fluid in the tank 65a will escape into the sump 21a in the event pressure in the tank, due to supply of fluid from the cylinder 43 or otherwise, exceeds the predetermined limit.

Figs. 13 and 14 illustrate a tire construction adapted to be used for or incorporated in the wheels for the landing gears and the wheels for the retractible members l2, l2a, such construction being illustrated by way of example as mountings for the latter. Ma indicates the wheel axle supported at its opposite ends in the depending arms [2r of the adjacent retractible member and preferably fixed thereto by pins 14a. 76 indicates the wheel rim having adjacent its opposite ends off-set annular walls formcylmder 69, in which is mounted a piston 10.

ing chambers 15a for anti-friction bearings 15, preferably of the roller type, whereby the wheel is free to turn on the axle Ma. The bearings are held in the chambers 1511 by ring nuts 15a threaded into the side Walls of the chambers.

The tire is mounted on and secured to the rim and consists of a carcass or casing 16 and two inner tubes Tl enclosed therein in side by side relation, these parts being so arranged that either tube l1 may be inflated or deflated independently of the other tube and accordingly it will be Observed that if either inner tube is punctured or becomes deflated for any reason the other tube (if inflated) will maintain the carcass 16 in a partially expanded condition, so that operability of the wheel will not be seriously impaired. As shown, the carcass 16 consists of a tread portion 16a, side walls having extensions 16b extending throughout the circumference thereof and adapted to lie flat on the run 15 and an intermediate or division wall 760 extending inwardly radially from the center line of the tread portion 76a throughout the circumference of the latter and anchored throughout its periphery, in the manner later set forth. The marginal edge portion of the extensions 16b are thickened to form circumferential shoulders 18, which are preferably under-cut and project into under-cuts formed in the end walls of the chambers 15a.

The wall 760 extends inwardly so as to fit beformed in the shoulders 18, so that suitable countersunk screws 19 extending through openings formed in the side wall of one chamber a, the

openings in the shoulders 78 and wall 160 and threaded into threaded openings formed in the side wall of the other chamber 15a, may rigidly secure these parts together. As shown, the wall 160, portions of the tread 16a, the side walls 161), and extensions 18?) form the casings for the tubes 11, which when inflated support the walls 18a and 16b as shown. The walls 18a, 1817, 181? and 180 are formed of composite rubber (or like substance) and corded fabric or other suitable material, so that the latter wall is capable of resisting stresses thereon in the event one of the tubes 11 is deflated and the tire is under load, as shown in Fig. 14.

It will be obvious that the sidewalls 18b and tread portion may be suitably reinforced with one or more piles of material. a

The shock absorbing means l3 incorporated in each retractile member |2, |2a, consists of the following instrumentalities; |3a indicates an inner hollow member having an inner end wall 18 abutting the transverse wall |8x of the element l8 and secured to the latter by countersunk screws 19a. The outer end of the member |3a is provided with a removable closure 88 having screw threaded connection with the inner wall of the member Ha. Ha indicates a hollow outer member telescopically fitting the outer wall of the member |3a and inner wall of the element |8. The outer end of the member l3a' is provided with a closing member 88a, preferably screw threaded thereinto, the closing member 88a being preferably integral with and forming the support for the wheel carrying arms In. The closing member 88a is formed with an axially disposed opening 88a which is enlarged at itslower end. The opening 88a forms a seat for the lower end of a hollow rod 8|, such end being closed by a screw plug 82, the flange of which engages the bottom wall of the enlarged portion of the opening 88a so as to secure the rod to the closing member 88a.

The upper end of the rod 8| slidably extends through an axially disposed opening 83 formed in the closure 88 and is provided at its upper end with a piston 84 slidably engaging the inner wall of the member l3a. The member |3a is filled with air under pressure of approximately 500 pounds and a small quantity of oil to form a seal and the outer member |3a' is filled with a quantity of fluid (oil) and air under pressure, the upper ends of the spaces in these members being in communication by a duct 85 formed in the wall of the member |3a, whereby the pressure of the air therein is equalized. The lower end portion of the rod 8| is formed with one or more inlets 8|a for the oil and its upper end portion is formed with one or more outlets 8|a' for the oil, the outlets being normally closed by a valve 86. The valve88 consists of a hollow member slidably fitting the inner wall of the rod 8| and an opening 8|b formed in the piston 84 in alinement with the rod 8|. The side walls of the valves 88 are formed with ports arranged to register with the outlets 8|a' when raised or moved upwardly. The valve 86 isnormally biased downwardly into position to close the outlets 8 la by a spring 88a, which abuts the top wall of the valve and a screw cap83 threaded into the upper end of the rod 8|, the spring being designed 18 to balance any static load tomaintain the valve 86 in normal position (see Fig. 13) when the airplane is at rest or taxiing on level terrain, but when taxiing on rough terrain or in landing the spring 88a yields due to excess pressure on the valve; that is, when the outer member Be is forced inwardly (see Fig. 14), pressure of the oil on the valve 88 forces it upwardly against the tension of the spring 88a whereby the ports in the valve register with the outlets 8|a' to permit flow of the oil through the latter into the member |3a below the piston 84. As will be observed the inward movement ofthe member 3a serves to furflow of the oil into the outer member I811.

ther compress the air in both members l3a, l3a, which compression is utilized to force the outer member l3a" outwardly upon release of the load thereon. Upon relief of the inward pressure on the member Ba, and movement thereof to or toward its outer position, the oil in the member [3a flows through a plurality of valves 81, which being relatively small, serveto retard such movement. Each valve 81 consists of a tube closed at its lower end and slidably fitting a through opening 88:: formed in the closure 88. The upper end of the tube is provided with a flange 81a which is engaged by a coiled spring 88 surrounding the tube and seated on the bottom wall of the enlarged portion of the spring 889:. The spring 88 normally serves to support the tube 81 against downward movement, so that a port 89 in the side wall thereof is closed by the wall of the opening 880:, but-upon relief of upward pressure on the outer member |3a', the pressure of the fluid in the inner member |3a serves to move the tube 81 downwardly against the influence of the spring 88 whereby the port in the side wallthereof is moved to a position below the closure 88 to permit Annular member 81a mounted on the closure 88 concentric to the openings 88:0 limit the upward movements of the valves 81. The piston 84 is formed with a plurality of through ducts 9| so that a small quantity of the oil may be maintained thereabove for sealing the walls of the piston. As shown in Fig.14, when theouter member is moved inwardly, portions of the oil are forced. through theducts 9| into the space above the piston, but when the outer member moves outward excess oil is forced back through these ducts, due to the air pressure in the inner member |3a, into the recess 82 provided on the inner face of the piston 84. The engagement of the piston 84 with the closure 88 serves to limit the outward movement of the outer member l3a.

It will also be observed that I provide a dual piston form of'construction so arranged that in the return of the parts to normal position the compressed air operates uniformly and simultaneously on both pistons, that is, the piston 84 and closing member 88a, during return flow of the oil through the valves 81, the effect of which is to reduce the load on the hollow rod 8| approximately one-half. In the up-stroke of the pistons 84, 8811, the pressure of the air in the members l3a, Ha, is equalized, since the oil forces the piston 84 upwardly and therefore the rod 8| is relieved of any load and serves only to connect the pistons together and as a conduit for the oil.

Air under pressure is supplied to the members |3a, l3a, through a conduit 93formed in the closure member 88a and the outer wheel'supporting arm I2x, the outer end of the conduit being closed by a screw plug 84 having a suitable valved port therein. The required quantity of oil for the member 13a isalso'supplied thereto through: the

conduit'93;

It will be understood that the shock absorbing means l3 are mounted on the outer end of each retractile member I2, Ma, and are operablein any projected position of the latter.

62a indicates a throw-out switch (see Fig. 9a).

In the form of construction illustrated eitheror both end portions of: the fuselage 2 may be utilized for storage of goods,- equipment and supplies, as well as to permit access tothe mecha nisms I I, Ho, and other equipment.

For these purposes; I provide floors 95 and transverse partitions 96; the latter being spaced longitudinally of the fuselage. The retractile members [2, [2a, extendth-rough openings formed inthe floors. As already set forth each member I2, l2a, is removable through the adjacent opening [d, but in some instances; to inspect or service each. member, it may be moved upwardly endwise a short distance and thenits lower end swung inwardly and supported on the keelor the member may be: bodily positioned on its-side wall (cylinder I-6) on the keel. To pe'rmit of these operations, those portions of the floors, indicated at 95', between the members I2, [2a, are detachable from adjacent portions of the floors and removably supported on blocks or brackets 91 fixed to the inner ends-of the partitions 96.

In providing relatively movable retractile; wheel mounted members at theopposite ends of the fuselage and providing means for rotating these members, whereby the wheels may be posi-' tioned either for steering or to permit tilting, various operations maybe carried out independently of the speed ofthe airplaneand the speed of its propeller, so that steering and maneuvering operations of the airplane are not dependent upon its rudder; also,,this form of construction enables the airplane to be operated under certain adverse conditions; for example in the event the propellingmeans on one wing becomes inoperative, this would not preclude steering or maneuvering of the=airplanein any desired direction: by operation. of the other propelling means and rotating theme'mbers l2, l 2a, of the retractile mechanism which areinengagement with the terrain.

To those skilled in the art towhich myinvention relates many changes inconstruction and widely differing embodiments and applications of the invention will be apparent without depart ing from the spirit and scope thereof; My disclosure and the description hereinare purely illustrative and not intended tobe inany sense limiting.

What I claim is:

I 1. In an airplane, the combinationwith a fuselage or hull-andalanding gear mechanism therefor,v ofa retractile mechanism. mounted in said fuselage or hull adjacent one end thereof and comprising telescopically related elements the outer one of which is rotatably mounted in said fuselage and the inner elementsbeing arranged to be projected outwardly relativeto said outer element and each other, said innermost elementbeing provided at its outer end with a wheel for engagement with a landing. surface for co-operation with said landing gear mechanism, means between each of said elements and the-adjacent element or elements for preventing rotation thereof one relative to the other, means foroperating each of said inner elements-outwa y d;

20 inwardly, and means for rotating said outer elements.-

2. In an airplane having a fuselage or hull and wing structures at opposite sides thereof, the combination witha landing gear below each said wing structure, of a retractile mechanism consisting ofmember rotatably mounted in said fuselage or hull adjacent one end thereof, endwise relatively movable elements movable outwardly relative thereto for engaging one of said elements with a landing surface and means for maintaining said member and respective elements in non-rotative' relation, a wheel mounted on the outer end of said surface engaging element, with its axis cutting the longitudinal axis of said member, means for operating said member outwardly and inwardly, and means for rotating said member.

3. In an airplane having a fuselage and wing structures at opposite sides thereof, of landing gears intermediate the ends of said fuselage and below said wing structures, retractile mechanisms mounted within said fuselage forward and rearward of said landing gears, each said mechanism comprising a pair of members mounted at opposite sides of the longitudinal axis of said fuselage and each including an element movable outwardly for engagement with the terrain, and power means for independently moving each of said elements outwardly and inwardly.

4. In an airplane, the combination of a cylinder mounted in one end portion of the airplane, a head fixedly mounted in said cylinder, acylindrical element surrounding said head and provided outwardly thereof with a transverse wall forming a piston arranged to move outwardly and inwardly relative to said cylinder, said element being provided intermediate its ends with an external circumferential wall, a cylindrical element between said cylinder and said first-mentioned cylindrical element and provided at its outer end portion with an internal circumferential wall disposed in the path of movement of said first mentioned wall, whereby movement of said first mentioned element outwardly effects engagement of said walls and movement of said last mentioned element outwardlyrelative to said cylinder, said last mentioned element having at its inner end an external circumferential wall, a ground engagingmember mounted on the outer end of said first mentioned element, hydraulic means for operating said piston outwardly and inwardly, and hydraulic means for moving said last mentioned elementinwardly.

5. In an: airplane, the combination of a cylinder mounted in one end portion of the airplane, a head fixedly mounted -1'n said cylinder intermediate the ends thereof, a cylindrical element normally disposed insaid cylinder around said head and provided at its outer end: with a wall outwardly of said head, said head and end wall being formed with alined through openings, a

separate cylindrical element; normally disposed within said cylinder in surrounding relation to said first-mentioned cylindricalelement and movable endwise' relative'thereto and provided at its outer end with a member for engagement with the terrain, said last mentioned element being provided with a transverse wall outwardly of said end wall, means for limiting the outward movement of said last'men-tioned element, means for" supplying fluid under pressure to said head for first applying pressure to'the transverse wall onsaidlast-mentioned element tomove it a predetermined distance and fill the space therein 21" with fluid and thereafter for applying pressure to said transverse wall on said first mentioned element to move both said elements a predetermined distance. i

6. In an airplane, the combination of a cylinder mounted in one end portion of said fuselage, a fixed tubular member extending into said cylinder and provided at its inner end with a head, said head being formed with a through opening leading from said tubular member, a cylindrical element slidably fittingsaid head at its outer end portion and provided internally at its inner end with an annular wall slidably fitting said tubular member, said element being provided with an end wall outwardly of said head and said wall being formedwith 'a'port, a separate cylindrical element normally mounted within said cylinder and movable outwardly relative thereto, said separate element being provided at its outer end with a member for engagement with the terrain and a transverse wall outwardly of said first mentioned end wall, means for. supplying fluid under pressure through said tubular member and opening in said'head tosaid transverse wall to move said separate element outwardly and then to said end Wall to move both said elements outwardly, andmeans for moving said first-mentioned element inwardly, comprising a conduit leading through said tubular member and connected to the inner end of the space between it and said element and a pump for supplying fluid under pressure through said conduit to said space. V

7. An airplan as claimed in claim 4 wherein shock absorbing means are provided between said terrain engaging device and its carrying element.

8. In an airplane, the combination of a cylinder adapted to be mounted in one end portion of the airplane, a head fixedly mounted in said cylinder and formed with a through'opening, an inner cylindrical element slidably engaging said head and normally filled with fluid and provided with a piston outwardly of said head, said piston being formed with a throughv opening, an outer cylindricalelement slidably fitting the outer end of said cylinder and provided at its inner end with an external piston slidably fitting said cylinder and provided at its outer end with an internal shoulder, the space between said cylinder and outer element being normally filled with fluid, an intermediate cylindrical element between said inner and outer elements and provided with a piston outwardly of the piston on said inner element and carrying at its outer end a device for engaging the terrain and provided intermediate its ends with an external shoulder arranged to engage the shoulder on said outer element to move the latter outwardly, a pump having connections with said head for applying pressure therethrough to the piston on said intermediate element to move the latter outwardly, a pump for withdrawing fluid from the space between said cylinder and outer element during outward movement of the latter, and a pump for withdrawing fluid from said inner element during outward movement thereof.

9. In an airplane, the combination of a cylinder adapted to be mounted in the airplane with its outer end in registry with an opening in its wall, an element normally mounted within said cylinder and slidable outwardly and inwardly relative thereto through said opening, hydraulic means for operating said element, the outer end portion of said element being provided with a chamber, and shock absorbing mechanism mounted in said chamber, said mechanism comprising an inner inverted cylinder, an outer cylinder having a closed outer end carrying a terrain engaging member and telescopically fitting said inner cylinder, a closure carried by said inner cylinder, said cylinders being charged with a gas under pressure and'the outer cylinder being partially filled with liquid, the gas normally maintaining said cylinders-in" expanded relation, a-piston slidably fitting the wall 'of said inner cylinder, connections between said piston and said outer cylinder, saidconnections including means permitting flow ofthe liquidfrom said outer cylinder to said inner cylinder during inward movement of said outer cylinder, and a bypass valve mounted in said closure.

10. In an airplane, the combination of a cylindrical support arranged to depend from'one end portion of the airplane, an inner inverted cylinder fixedlymounted in said support in concentric spaced relation to the walls thereof, an outer cylinder telescopically fitting walls of said inner cylinder and said support, and provided with an outer end wall having a terrain engaging device, a closure for the outer end of said inner cylinder, said cylinders being charged with'a gas under pressure and the outer cylinder being partially filled with liquid, the gasnormally maintaining-said cylinders in expanded relation, a piston slidably fitting'the wall of said inner cylinder, connections between said pistonand said outer cylinder, said connections including means permitting flow of the liquid from said outer cylinder to said inner cylinder during inward movement of said outer cylinden'and a bypass valve mounted in saidclosure. v i

11. In an airplane having a fuselage, the'combination of a cylinder adapted to be rotatably mounted in the airplane, a member in said cylinder connected thereto for rotation with said cylinder (and movable'endwise relative thereto, a wheel mounted on the outer end of said member, normally disposed parallel to said fuselage, hydraulic means for rotating said cylinder through an arc in either direction, and power driven gearing for rotating said cylinder through anarc in either direction.

12. In an airplane,'the combination or a cylinder adapted to be rotatably mounted in the airplane, a member in said cylinder connected thereto for rotation with said cylinder and movable endwise relative thereto, a wheel mounted on the outer end of 'said member, normally disposed parallel to thelongitudinal axis of the airplane, power'driv-en gearing for rotating said cylinder through an arc in either direction, hydraulic means for rotating said cylinder through an arc in either direction, said hydraulic means including a normally closed control valve, and means for operating said valve to open position and releasing it for operation to closed position to stop the operation of said hydraulic means.

13. In a shock absorbing means for a portable vehicle, the combination with a member adapted to be mounted on the body of the vehicle, of an inner inverted cylinder having a closure mounted in its open end and filled with a gas under pressure, an outer cylinder telescopically fitting between said inner cylinder and said member and having an outer end wall carrying a terrain engaging device, said outer cylinder being partially filled with gas under pressure and liquid, a gas connection between said cylinders, whereby the pressure therein is maintained equalized, the gas pressure serving normally to maintain said "cylinders in expanded relation, a piston within and 's'li'dably fitting the Walls of the said inner cylinder, means connecting said piston to the end wall of said outer cylinder, :said connecting means including a valve to permit 'flowof liquid iromtsaid outer cylinder to said inner cyllnder during inward movement of said outer cyl- 4 in'cler relative to said inner cylinder, and a bypass valve mounted in said closure to permit return flow of the liquid during movement of said outer cylinder in the opposite direction.

14. A vehicle :as claimed in claim 13, wherein the first mentioned valve is normally closed but automaticallyopens due to excess pressure on the liquid in the outer cylinder upon movement of the latter inwardly.

15. In an airplane, the combination with. a fuselage and :aianding .gear mechanism therefor, oi adjustable-mechanism adjacent one end of said fuselage for co-operating with said landing gear mechanism for supporting said fuselage in making landings or take-ofis and for movably supporting it when on a landing surface, said adjustable mechanism consisting of an outer member mounted in :said fuselage and a plurality of concentrically related, endwise relatively movable members movably mountedinsald outer member, the innermost'member being provided on its outer end with a ground engaging device, and hydraulically operated means within :and between said member for initially :moving said innermost member outwardly apredetermined distance and for operating .said other inner members to :move said innermost member outwardly other predetermined distances.

16. In an airplane having a fuselage, the combination with a landing gear mechanism, of a retractile mechanism mounted in said fuselage adjacent one end thereohsaid retractile mechanism comprising a pair of spaced members each consisting of endwise relatively movable, nonrotatively related elements, the outermost one of which is rotatably mounted in said fuselage, means for operating certain of the remaining elements outwardly for cooperating with said landing gear mechanism, means connected with said outermost elements for simultaneousiyrotating said members, and aground engaging device mounted on the "outer end of one-of said remaining elements.

17. In an airplane having a fuselage, the combination with a landing gear mechanism, ofa retractile mechanism mounted in said fuselage adjacent :one end thereof, said retraetile mechanism comprising a pair of spaced members each com sistlng of endwise relatively movable, non-rotatively "related elements, the outermost one of which is rotatably mounted in said fuselage, means for operating certain of the remaining elements outwardly for cooperating with said landing gear mechanism, means connected with said outermost elements for simultaneously rotating said members, separate means for rotating each member independently of the other member, and a ground engaging device mounted on the outer end of one of said remaining elements.

18. In an airplane having a fuselage, the combination with a landing gear mechanism, of a retractile mechanism mounted in said fuselage adjacent one end thereof, said retractile mechanism comprising a, pair of spaced members each consisting of endwise relatively movable, nonrotatively related elements, the outermost element of one of said members being rotatably mounted in said fuselage, means for operating certain of the remaining elements outwardly for cooperating with said landing gear mechanism, a ground engaging device mounted on the other endxof one of said remaining elements, and means connected with said rotatable outermost element for rotating it to position the adjacent ground engaging device at an angle to the longitudinal axis of the fuselage.

EDWARD E. WALLACE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,404,532 Lehr Jan. 24, 1922 1,482,520 Lyon Feb. 5, 1924 1,497,584 Petey June 11, 1924 1,576,342 McElhaney ;1 Mar. 9, 1926 1,716,439 Gray June 11, 1929 1,842,776 Bogoslowsky Jan. 26, 1932 1,930,922 Burnelli Oct. 17, 1933 1,981,856 Downey Nov. 27, 1934 2,049,209 Bogoslowsky July 28, 1936 2,075,042 Knerr Mar. 30, 1937 2,156,288 Holliday May 2, 1939 2,159,058 Taylor et al. May 23, 1939 2,191,359 Thornhill "Feb. 20, 1940 2,224,641 Burnelli Dec. 10, 1940 2,233,411 Conklin Apr. 15, 1941 2,276,466 Cleveland Mar. 17, 1942? 2,313,242 Johnson Mar. 9, 1943. 2,323,279 Van Zelm June 29, 1943 

